FRP-strengthened RC beams. II: assessment of debonding strength models

Reinforced concrete (RC) beams strengthened in flexure by the bonding of a fiber reinforced polymer (FRP) plate to the tension face are susceptible to brittle debonding failures. Such failures commonly initiate at or near one of the plate ends at a load below that to achieve flexural failure of the plated section. For a successful design of flexural strengthening using FRP composites, it is important to be able to predict such plate end debonding failures. In the first of these two companion papers, 12 plate end debonding strength models have been reviewed and summarized (Engng Struct 24(4) (2002) 385–395). The aim of the present paper is to provide a comprehensive assessment of the strengths and weaknesses of all the 12 models. To this end, a large test database containing the test results of 59 beams reported to have failed by plate end debonding is first presented. This database was carefully constructed from an extensive survey of the published literature. Both statistical and graphical comparisons between test results and the predictions of the debonding strength models are next presented. A new simple debonding strength model which is superior to existing models is also proposed.